vendor: add buildkit

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/github.com/tonistiigi/fsutil/diskwriter.go

@@ -0,0 +1,352 @@
+package fsutil
+
+import (
+	"context"
+	"hash"
+	"io"
+	"os"
+	"path/filepath"
+	"strconv"
+	"sync"
+	"time"
+
+	"github.com/opencontainers/go-digest"
+	"github.com/pkg/errors"
+	"github.com/tonistiigi/fsutil/types"
+	"golang.org/x/sync/errgroup"
+)
+
+type WriteToFunc func(context.Context, string, io.WriteCloser) error
+
+type DiskWriterOpt struct {
+	AsyncDataCb   WriteToFunc
+	SyncDataCb    WriteToFunc
+	NotifyCb      func(ChangeKind, string, os.FileInfo, error) error
+	ContentHasher ContentHasher
+	Filter        FilterFunc
+}
+
+type FilterFunc func(string, *types.Stat) bool
+
+type DiskWriter struct {
+	opt  DiskWriterOpt
+	dest string
+
+	wg     sync.WaitGroup
+	ctx    context.Context
+	cancel func()
+	eg     *errgroup.Group
+	filter FilterFunc
+}
+
+func NewDiskWriter(ctx context.Context, dest string, opt DiskWriterOpt) (*DiskWriter, error) {
+	if opt.SyncDataCb == nil && opt.AsyncDataCb == nil {
+		return nil, errors.New("no data callback specified")
+	}
+	if opt.SyncDataCb != nil && opt.AsyncDataCb != nil {
+		return nil, errors.New("can't specify both sync and async data callbacks")
+	}
+
+	ctx, cancel := context.WithCancel(ctx)
+	eg, ctx := errgroup.WithContext(ctx)
+
+	return &DiskWriter{
+		opt:    opt,
+		dest:   dest,
+		eg:     eg,
+		ctx:    ctx,
+		cancel: cancel,
+		filter: opt.Filter,
+	}, nil
+}
+
+func (dw *DiskWriter) Wait(ctx context.Context) error {
+	return dw.eg.Wait()
+}
+
+func (dw *DiskWriter) HandleChange(kind ChangeKind, p string, fi os.FileInfo, err error) (retErr error) {
+	if err != nil {
+		return err
+	}
+
+	select {
+	case <-dw.ctx.Done():
+		return dw.ctx.Err()
+	default:
+	}
+
+	defer func() {
+		if retErr != nil {
+			dw.cancel()
+		}
+	}()
+
+	destPath := filepath.Join(dw.dest, filepath.FromSlash(p))
+
+	if kind == ChangeKindDelete {
+		if dw.filter != nil {
+			var empty types.Stat
+			if ok := dw.filter(p, &empty); !ok {
+				return nil
+			}
+		}
+		// todo: no need to validate if diff is trusted but is it always?
+		if err := os.RemoveAll(destPath); err != nil {
+			return errors.Wrapf(err, "failed to remove: %s", destPath)
+		}
+		if dw.opt.NotifyCb != nil {
+			if err := dw.opt.NotifyCb(kind, p, nil, nil); err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+
+	stat, ok := fi.Sys().(*types.Stat)
+	if !ok {
+		return errors.Errorf("%s invalid change without stat information", p)
+	}
+
+	statCopy := *stat
+
+	if dw.filter != nil {
+		if ok := dw.filter(p, &statCopy); !ok {
+			return nil
+		}
+	}
+
+	rename := true
+	oldFi, err := os.Lstat(destPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			if kind != ChangeKindAdd {
+				return errors.Wrapf(err, "invalid addition: %s", destPath)
+			}
+			rename = false
+		} else {
+			return errors.Wrapf(err, "failed to stat %s", destPath)
+		}
+	}
+
+	if oldFi != nil && fi.IsDir() && oldFi.IsDir() {
+		if err := rewriteMetadata(destPath, &statCopy); err != nil {
+			return errors.Wrapf(err, "error setting dir metadata for %s", destPath)
+		}
+		return nil
+	}
+
+	newPath := destPath
+	if rename {
+		newPath = filepath.Join(filepath.Dir(destPath), ".tmp."+nextSuffix())
+	}
+
+	isRegularFile := false
+
+	switch {
+	case fi.IsDir():
+		if err := os.Mkdir(newPath, fi.Mode()); err != nil {
+			return errors.Wrapf(err, "failed to create dir %s", newPath)
+		}
+	case fi.Mode()&os.ModeDevice != 0 || fi.Mode()&os.ModeNamedPipe != 0:
+		if err := handleTarTypeBlockCharFifo(newPath, &statCopy); err != nil {
+			return errors.Wrapf(err, "failed to create device %s", newPath)
+		}
+	case fi.Mode()&os.ModeSymlink != 0:
+		if err := os.Symlink(statCopy.Linkname, newPath); err != nil {
+			return errors.Wrapf(err, "failed to symlink %s", newPath)
+		}
+	case statCopy.Linkname != "":
+		if err := os.Link(filepath.Join(dw.dest, statCopy.Linkname), newPath); err != nil {
+			return errors.Wrapf(err, "failed to link %s to %s", newPath, statCopy.Linkname)
+		}
+	default:
+		isRegularFile = true
+		file, err := os.OpenFile(newPath, os.O_CREATE|os.O_WRONLY, fi.Mode()) //todo: windows
+		if err != nil {
+			return errors.Wrapf(err, "failed to create %s", newPath)
+		}
+		if dw.opt.SyncDataCb != nil {
+			if err := dw.processChange(ChangeKindAdd, p, fi, file); err != nil {
+				file.Close()
+				return err
+			}
+			break
+		}
+		if err := file.Close(); err != nil {
+			return errors.Wrapf(err, "failed to close %s", newPath)
+		}
+	}
+
+	if err := rewriteMetadata(newPath, &statCopy); err != nil {
+		return errors.Wrapf(err, "error setting metadata for %s", newPath)
+	}
+
+	if rename {
+		if oldFi.IsDir() != fi.IsDir() {
+			if err := os.RemoveAll(destPath); err != nil {
+				return errors.Wrapf(err, "failed to remove %s", destPath)
+			}
+		}
+		if err := os.Rename(newPath, destPath); err != nil {
+			return errors.Wrapf(err, "failed to rename %s to %s", newPath, destPath)
+		}
+	}
+
+	if isRegularFile {
+		if dw.opt.AsyncDataCb != nil {
+			dw.requestAsyncFileData(p, destPath, fi)
+		}
+	} else {
+		return dw.processChange(kind, p, fi, nil)
+	}
+
+	return nil
+}
+
+func (dw *DiskWriter) requestAsyncFileData(p, dest string, fi os.FileInfo) {
+	// todo: limit worker threads
+	dw.eg.Go(func() error {
+		if err := dw.processChange(ChangeKindAdd, p, fi, &lazyFileWriter{
+			dest: dest,
+		}); err != nil {
+			return err
+		}
+		return chtimes(dest, fi.ModTime().UnixNano()) // TODO: parent dirs
+	})
+}
+
+func (dw *DiskWriter) processChange(kind ChangeKind, p string, fi os.FileInfo, w io.WriteCloser) error {
+	origw := w
+	var hw *hashedWriter
+	if dw.opt.NotifyCb != nil {
+		var err error
+		if hw, err = newHashWriter(dw.opt.ContentHasher, fi, w); err != nil {
+			return err
+		}
+		w = hw
+	}
+	if origw != nil {
+		fn := dw.opt.SyncDataCb
+		if fn == nil && dw.opt.AsyncDataCb != nil {
+			fn = dw.opt.AsyncDataCb
+		}
+		if err := fn(dw.ctx, p, w); err != nil {
+			return err
+		}
+	} else {
+		if hw != nil {
+			hw.Close()
+		}
+	}
+	if hw != nil {
+		return dw.opt.NotifyCb(kind, p, hw, nil)
+	}
+	return nil
+}
+
+type hashedWriter struct {
+	os.FileInfo
+	io.Writer
+	h    hash.Hash
+	w    io.WriteCloser
+	dgst digest.Digest
+}
+
+func newHashWriter(ch ContentHasher, fi os.FileInfo, w io.WriteCloser) (*hashedWriter, error) {
+	stat, ok := fi.Sys().(*types.Stat)
+	if !ok {
+		return nil, errors.Errorf("invalid change without stat information")
+	}
+
+	h, err := ch(stat)
+	if err != nil {
+		return nil, err
+	}
+	hw := &hashedWriter{
+		FileInfo: fi,
+		Writer:   io.MultiWriter(w, h),
+		h:        h,
+		w:        w,
+	}
+	return hw, nil
+}
+
+func (hw *hashedWriter) Close() error {
+	hw.dgst = digest.NewDigest(digest.SHA256, hw.h)
+	if hw.w != nil {
+		return hw.w.Close()
+	}
+	return nil
+}
+
+func (hw *hashedWriter) Digest() digest.Digest {
+	return hw.dgst
+}
+
+type lazyFileWriter struct {
+	dest     string
+	ctx      context.Context
+	f        *os.File
+	fileMode *os.FileMode
+}
+
+func (lfw *lazyFileWriter) Write(dt []byte) (int, error) {
+	if lfw.f == nil {
+		file, err := os.OpenFile(lfw.dest, os.O_WRONLY, 0) //todo: windows
+		if os.IsPermission(err) {
+			// retry after chmod
+			fi, er := os.Stat(lfw.dest)
+			if er == nil {
+				mode := fi.Mode()
+				lfw.fileMode = &mode
+				er = os.Chmod(lfw.dest, mode|0222)
+				if er == nil {
+					file, err = os.OpenFile(lfw.dest, os.O_WRONLY, 0)
+				}
+			}
+		}
+		if err != nil {
+			return 0, errors.Wrapf(err, "failed to open %s", lfw.dest)
+		}
+		lfw.f = file
+	}
+	return lfw.f.Write(dt)
+}
+
+func (lfw *lazyFileWriter) Close() error {
+	var err error
+	if lfw.f != nil {
+		err = lfw.f.Close()
+	}
+	if err == nil && lfw.fileMode != nil {
+		err = os.Chmod(lfw.dest, *lfw.fileMode)
+	}
+	return err
+}
+
+func mkdev(major int64, minor int64) uint32 {
+	return uint32(((minor & 0xfff00) << 12) | ((major & 0xfff) << 8) | (minor & 0xff))
+}
+
+// Random number state.
+// We generate random temporary file names so that there's a good
+// chance the file doesn't exist yet - keeps the number of tries in
+// TempFile to a minimum.
+var rand uint32
+var randmu sync.Mutex
+
+func reseed() uint32 {
+	return uint32(time.Now().UnixNano() + int64(os.Getpid()))
+}
+
+func nextSuffix() string {
+	randmu.Lock()
+	r := rand
+	if r == 0 {
+		r = reseed()
+	}
+	r = r*1664525 + 1013904223 // constants from Numerical Recipes
+	rand = r
+	randmu.Unlock()
+	return strconv.Itoa(int(1e9 + r%1e9))[1:]
+}